Unit 4.1: Overview of the Cardiovascular System & the Heart

Question 1

What do we require from the environment?

Answer 1

Nutrients and oxygen

Question 2

How do we overcome the diffusion limitation of oxygen and nutients?

Answer 2

1) cardiovascular system for transport of substances through the body
2) transported by flow of blood through circulatory system
3) bulk flow rather than diffusion

Question 3

What is transported from the external environment to tissues?

Answer 3

Nutrients, water, gases (especially O2)

Question 4

What is transported between tissues of body?

Answer 4

Wastes, nutrients and hormones

Question 5

What is transported from tissues to external environment?

Answer 5

Metabolic wastes, gases (especially CO2), heat

Question 6

What are the components of the cardiovascular system?

Answer 6

Heart (pumps)
Blood vessels (vasculature)
Blood cells & plasma (fluid)

Question 7

What is the pericardium?

Answer 7

A tough membranous sac surrounding the heart

Question 8

What is the structure of the pericardium?

Answer 8

Made up of 2 layers with a small amount of fluid between them that acts as lubricant

Question 9

What do the coronary arteries do?

Answer 9

Nourish the heart muscle

Question 10

What happens when there’s a lack of supply to the heart?

Answer 10

Leads to a heart attack (myocardial infraction)

Question 11

What are the components of the internal anatomy of the heart?

Answer 11

1. Left Atrium
2. Left ventricle
3. Right Atrium
4. Right Ventricle
5. Valves

Question 12

What is the course of blood in the heart?

Answer 12

Venae cavae > Right atrium > Right ventricle > Lungs > Pulmonary veins > Left atrium > Left ventricle > sends to body via aorta

Question 13

What is the function of valves?

Answer 13

They ensure that the flow of blood is unidirectional (one-way)

Question 14

Where are valves found?

Answer 14

At the entrance to the left and right ventricles

Not found at the atrium due to weak atrial contraction relative to ventricular contraction

Question 15

Why are there no valves at the atrium?

Answer 15

Atrial contraction compresses the veins at the entry to the heart which closes the exit to the heart and reduces backflow

Question 16

What are the different valves found in the heart?

Answer 16

AV valves (tricuspid -right and bicuspid/mitral - left)
Semilunar valves (aortic and pulmonary)

Question 17

Where are AV valves attached?

Answer 17

They are attached on ventricular side to collagenous cords (chordae tendinae) - prevents valves from being pushed back into atrium

Question 18

Where are semilunar valves?

Answer 18

Just inside aorta and pulmonary arteries (prevents backflow into ventricles)

Question 19

Why don’t semilunar valves need cords like AV valves?

Answer 19

Because of their shape

Question 20

What are the 2 divisions of the cardiovascular system?

Answer 20

1. Pulmonary circuit: blood vessels in the lungs and those that connect the lungs to the heart
2. Systemic circuit: encompasses the rest of the blood vessels in the body

Question 21

What is the path of blood in the pulmonary circuit?

Answer 21

Right atrium > Right ventricle > pulmonary arteries > Lungs > lungs have many small capillaries to increase O2 transfer (increases resistance and decrease pressure of blood) > oxygenated blood as low pressure so it returns to the heart with the help of pulmonary veins to left atrium

Question 22

What is the path of blood in the systemic circuit?

Answer 22

Left atrium > left ventricle > pumped to aorta that branches into smaller arteries and then to capillary networks throughout the body > O2 diffuses from the blood into the tissues in the capillary beds > flow to small venules and then larger veins > oxygen poor blood has low pressure so it need help to return to heart (via superior/inferior vena cava to right atrium)